Development Of New Slags For Bearing Steel GCr15 By Electroslag Remelting Withdrawing

Bearing steel, with high contact fatigue strength and abrasion strength, is mainly used to produce rolling elements for rolling bearing, tool and mould for machining.Therefore bearing steel is widely used in mechanical manufacturing, railway transportation, autombile manufacturing and national defense industry. Bearing steel is usually smelted by LF furnace and converter process, Electroslag remelting(ESR)is a suitable process for high quality bearing steel, especially for high speed aviation bearing, due to its ability to improve the purity, macrostructure, the distribution and size of carbide and low low-temperature impact toughness. But the only single ingot can be obtained by ESR process for bearing steel. The cogging and forging process must be performed for ESR ingot before hot rolling. In this paper, the new electroslag continue casting technology was used to producing the GCr15 bearing steel, however there are also steel leakage, leakage slag surface problems in this process. The development and application of the new slags are the key to solve the problems above.Based on consulting a lot of references about electroslag remelting and GCr15 bearing steel, for the current problems, the new experiment slag systems,L1,L2 and L3 are designed for electroslag process with withdrawing of ingot. The test devices of melting temperature and viscosity properties were used to measure the melting temperature and viscosity properties of the new and original slags. The parameters of physical chemistry properties of the new and original slags such as the density and optical basicity were calculated by the empirical equations. The physical chemistry properties of the new slag were obtained through experiment testing and calculation.the melting points of new slags L2,L3 were lower than traditional ANF-6 slag system.In high temperature, the viscosity stability of all the new slags were better than ANF-6; especially L2,L3 slag systems which were long slags. The densities of three slag systems were similar to ANF-6. The optical basicity of three slag systems was a little higher than that of ANF-6. The conductivity of three slag systems was less than that of ANF-6. L2,L3 slags were more suitable for production. So L2,L3 slags have been used to pratical production. The industrial experiments show that the L2,L3 slags, with better viscosity stability, can better meet the needs of actual production.Not only could the slags met the needs, but improved the surface quality. And the traditional characteristics of electroslag remelting process were maintained during the ESCC process, and inclusion of the ingot met the national standards.